Add the following lines to your script's [Files] section. (Change "vcfiles" to the path you extracted the files to.)
Note: It may not be necessary to install every file depending on your application's requirements. For example, mfc42u.dll is not necessary if your MFC application isn't Unicode-based.

If you're using an Inno Setup version prior to 3.0.5, you should upgrade. If that's not possible, then you need to add CopyMode: alwaysskipifsameorolder to each of the lines. (This isn't necessary on version 3.0.5 and later since it's the default behavior.)

Put all other files pertaining to your application after the "end VC system files" line.

Never pull in any of the system files from your own Windows System directory. If this advice is ignored, you risk potentially causing DLL version conflicts (like this one) on users' systems.

Administrative privileges are required

In order for the files with the restartreplace flag to install successfully on Windows NT/2000/XP, the user must have administrative privileges. By default, Inno Setup installations do not check for administrative privileges. It is recommended that make your installation script check for this, by setting the PrivilegesRequired [Setup] section directive:

[Setup]
...
PrivilegesRequired=admin
...

If this is not done, and the user doesn't have administrative privileges, an "Access Denied" error message will be displayed during the installation.

Revisions to this Document

2007-06-08:

Added OnlyBelowVersion: 0,6 parameters to each line to prevent Setup from trying to install the files on Windows Vista. All of the files come preinstalled on Vista already, and cannot be re-registered due to security restrictions on the registry.

2004-04-01:

Updated links for Visual Studio 6.0 Service Pack 6.

2004-03-29:

Added sharedfile flag to all the files, since some other installers incorrectly use shared file counting on them.

2003-09-03:

Removed CopyMode: alwaysskipifsameorolder from each of the lines since it's the default behavior in Inno Setup 3.0.5 and later.